JPH0734775A - Seal construction of arrival tunnel port of shield excavator - Google Patents

Abstract

PURPOSE:To eliminate rolling up of tunnel port sealant to prevent the incursion of ground water, etc., in the case a shield excavator is driven forward in an arrival vertical shaft. CONSTITUTION:Long strip shaped rolling-up preventing pieces 2, 2...2 are fixed to the circumference on the rear surface of a ring-shaped elastic sealant 1 loaded to a tunnel port B in the circumferential direction at proper intervals. In the case a shield excavator A is driven forward in an arrival vertical shaft C, the bending of the elastic sealant 1 in the direction of excavation is prevented by those rolling-up preventing pieces 2 to ensure the pressure-welding to the peripheral surface of the shield excavator A, and the incursion of ground water is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure provided at a wellhead on the arrival vertical shaft side of a shield excavator.

[0002]

2. Description of the Related Art When a shield excavator that has excavated a tunnel from a starting shaft side reaches the reaching shaft and enters the reaching shaft, it prevents groundwater and excavated sand from flowing into the reaching shaft. Conventionally, a seal device is arranged at the entrance of the reaching shaft to bring it into pressure contact with the outer peripheral surface of the shield excavator. As such a sealing device, as shown in FIG. 8, a pair of front and rear ring-shaped sealing members 21, 21 are attached to the inner peripheral surface of the reaching wellhead B having a diameter larger than the outer peripheral diameter of the shield excavator A. There is known a structure in which a ring-shaped wellhead seal member 22 is attached to the opening end of the wellhead B on the arrival vertical side.

In the sealing device having the above structure, when the shield excavator A enters, first, the sheath tube D with a lid having an inner diameter larger than that of the shield excavator A is inserted into the wellhead B from the reaching shaft C side. , The wellhead sealing material 22 is pushed toward the shield excavator A side, bent and brought into pressure contact with the outer peripheral surface of the sheath pipe D, and compressed air is supplied into the sheath pipe to make a pressure state, and then the shield excavator A is entered. Then, the pair of front and rear sealing materials 21, 21 are expanded and pressed against the outer peripheral surface of the shield excavator A while pressing the sealing materials 21, 21 to the shield shaft excavator A while preventing the inflow of groundwater or the like to the reaching shaft. Is possible.

[0004]

However, according to the above-described conventional sealing device, as shown in FIG. 9, as the shield excavator A enters the sheath pipe D, the sheath pipe D is relatively retracted. And a state in which the tip of the wellhead sealing material 22 is separated from the outer peripheral surface of the sheath D and bent in the inner diameter direction along the opening end surface of the sheath pipe D, and the tip is in contact with the outer peripheral surface of the shield excavator A. Become. When the shield excavator A is advanced while further retracting the sheath unit D from this state, the tip portion of the wellhead seal member 22 is shielded by the frictional force between the shield excavator A and the wellhead seal member 22, as shown in FIG. There is a problem that the excavator A is bent and rolled in the approach direction, and it becomes impossible to prevent the inflow of groundwater and the like.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a shield excavator which can prevent the inflow of groundwater and the like without failing to prevent the seal material from being rolled up. To provide a sealing structure.

[0006]

In order to achieve the above object, a seal structure of a reaching wellhead of a shield excavator of the present invention has a ring shape having a circular hole having a diameter smaller than the outer diameter of the shield excavator at the reaching wellhead. In a seal structure in which the elastic sealing material is mounted concentrically with the reaching wellhead, strip-shaped curl prevention pieces are fixed or embedded at appropriate intervals in the circumferential direction on the shield excavator arrival side rear surface of the elastic sealing material. It has the following structure.

In such a seal structure, claim 2
As described in the above, strip-shaped pressing pieces whose length is shorter than the width between the inner and outer peripheral edges of the elastic sealing material are provided on the front surface of the elastic sealing material which is provided with the curl prevention piece at appropriate intervals in the circumferential direction. Alternatively, the base of each pressing piece may be pivotally attached to the elastic seal member so as to be rotatable back and forth. Further, as described in claim 3, the curl prevention piece and the elastic seal are provided. It is desirable to have a structure in which the tip of the material is bent backward.

[0008]

[Function] The sheath pipe is inserted into the pit from the reaching vertical shaft side, and the ring-shaped elastic sealing material is bent in the direction along the inner peripheral surface of the pit and expanded. In this state, the shield excavator is advanced into the well, the tip of the shield excavator is housed in the sheath pipe, and when the sheath pipe is moved into the reaching shaft, the elastic sealing material is released from the open end of the sheath pipe. Although the elastic member is disengaged and tries to bend in the inner diameter direction by using the elastic restoring force as the fulcrum at the opening end face of the sheath tube, the strip-shaped curl prevention piece attached to the tip end of the elastic seal member causes the seal member to have a long length. It is held in the same plane as the vertical plane, and its tip is brought into contact with the outer peripheral surface of the shield excavator without bending.

When the shield excavator is further entered from this state, the elastic seal material tends to bend in the entering direction (front side) due to the sliding contact force with the outer peripheral surface of the shield excavator, but as described above, The curl preventive piece prevents the elastic seal material from inclining and refracting in the direction of entry of the shield excavator, and always keeps the inner peripheral end of the shield excavator while keeping it inclined toward the shield excavator side. Prevents inflow of groundwater etc. by making pressure contact with the outer peripheral surface of.

If the tip end of the curl prevention piece and the inner peripheral end of the elastic seal material are bent rearward, the inner peripheral end of the elastic seal material extends from the sheath pipe to the outer peripheral surface of the shield excavator. When transferred, the front side of the inner peripheral edge of the elastic seal material can be surely brought into contact with the outer peripheral surface of the shield excavator, and the elastic seal material will be inverted and bent forward by the frictional force with the shield excavator. Can be more firmly prevented.

Further, strip-shaped pressing pieces whose length is shorter than the width between the inner and outer peripheral edges of the elastic sealing material are arranged on the front surface of the elastic sealing material at appropriate intervals in the circumferential direction, and the base of each pressing piece is elastic. If it is pivotally attached to the seal material so that it can rotate back and forth, the tip of the pressing piece contacts the outer peripheral surface of the shield excavator and keeps the state inclined rearward, and receives the front surface of the elastic seal material. This prevents the elastic sealing material from expanding forward due to the infiltration pressure of groundwater or the like.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.
In FIGS. 1 and 2, reference numeral 1 denotes a ring-shaped elastic seal member made of an elastic material such as rubber, the inner diameter of which is the central hole 1a.
Is smaller than the outer diameter of the shield excavator A. On the rear surface of the ring-shaped elastic sealing material 1, curl preventing pieces 2, 2 ... 2 made of a metal plate, hard elastic rubber, or a synthetic resin plate having appropriate rigidity are attached at appropriate intervals in the circumferential direction. , Or fixed with bolts or the like.

The curl prevention piece 2 is formed in a strip shape that is long in the width direction between the inner and outer peripheral edges of the elastic seal material 1, and has its inner end edge aligned with the inner peripheral edge edge of the elastic seal material 1. The outer edge reaches the middle portion of the elastic seal material 1 in the width direction. Further, the inner end portion 2a of the curl prevention piece 2 is bent rearward so that the inner peripheral edge portion of the elastic sealing material 1 is also integrally bent and inclined rearward. The length of the curl prevention piece 2 may be such that it can prevent the inner peripheral end of the elastic seal material 1 from being folded back. In this embodiment, the outer peripheral surface of the shield excavator A and a sheath described later are used. The length is slightly longer than the dimension between the pipe D and the outer peripheral surface, and the outer edge of the pipe D does not reach the inner peripheral surface of the wellhead B described later.

Further, the gap between the curl prevention pieces 2 and 2 adjacent to each other in the circumferential direction of the elastic seal material 1 may be such that the elastic seal material 1 is allowed to expand and contract in the radial expansion direction. The interval is appropriately set depending on the material of the piece 2. That is, if the curl prevention piece 2 is made of a material having rigidity such as a metal plate or a synthetic resin plate, the gap between them becomes large, and it may be made of a plate material having an appropriate elasticity such as a hard rigid rubber plate. For example, when the gap is made of an elastic material, it is desirable to have an appropriate rigidity for holding a flat surface. Alternatively, a rigid plate-like material may be embedded inside the curl prevention piece 2 made of an elastic material. Furthermore, the curl prevention piece 2 may be embedded inside the elastic sealing material 1.

As shown in FIG. 3, the elastic seal material 1 provided with the curl prevention piece 2 is centered on the end face of the well B of the reaching shaft C which is open to the shaft C side. The hole 1a is concentric with the wellhead B, and the outer peripheral edge portion is fixed by bolts 3. Further, a pair of front and rear sealing materials 4, 5 whose inner diameters, that is, the diameters of the central holes 4a, 5a are smaller than the outer diameters of the shield excavator A are fixed to the inner peripheral surface of the wellhead B. In the figure, D is a sheath pipe that closes the wellhead B in an airtight state when the shield excavator A arrives, the rear end of which is entirely open and the front end of which is closed by an openable / closable closed door d. The outer diameter of the sheath pipe D is smaller than the inner diameter of the wellhead B, and the inner diameter is larger than the outer diameter of the shield excavator A.

Now, when the shield excavator A excavates the tunnel from the starting shaft side and reaches the reaching shaft C, the sheath pipe D is inserted from the hole B while expanding and bending the elastic sealing material 1 rearward, The excavated wall portion provided with the wellhead B is cut out from the inside of the sheath pipe D, and then the shield excavator A is advanced into the wellhead B. The open end of the wellhead B is closed by the insertion of the sheath pipe D. The insertion of the sheath pipe D causes the elastic seal material 1 to bend backward and its front inner peripheral portion to elastically contact the outer peripheral surface of the sheath pipe D. At the same time, compressed air is supplied to the inside of the sheath pipe D to prevent groundwater and the like from flowing into the wellhead B.

When the shield excavator A is propelled in this state, the shield excavator A enters while expanding the central holes of the front and rear seal members 4 and 5 attached to the inner peripheral surface of the wellhead B, and these The seal members 4 and 5 are pressed against the outer peripheral surface of the shield excavator A while being bent forward. Further, when the shield excavator A is propelled to reach the open end of the sheath pipe D, the sheath pipe D is moved in the direction of extracting from the wellhead B in synchronization with the approach of the shield excavator A.

By the movement of the sheath pipe D, the inner peripheral edge of the elastic seal material 1 at the wellhead B is separated from the open end of the sheath pipe D.
At this time, the elastic seal material 1 tends to bend in the inner diameter direction along the open end surface of the sheath tube D, but since the strip-shaped curl prevention piece 2 is provided on the inner peripheral portion of the rear surface of the sheath tube D, these The curl is prevented by the curl prevention piece 2. That is, the curl prevention piece 2 hardly bends due to its rigidity, and the inner peripheral portion of the elastic seal material 1 is oriented in the same direction as its flat surface in order to always maintain a flat plate state.

Therefore, when the inner peripheral edge of the elastic seal material 1 comes off the sheath pipe D and comes into contact with the outer peripheral surface of the tip of the shield excavator A, the curl prevention piece 2 is covered with the sheath pipe D as shown in FIG. From the open end toward the rear in a straight line, the inner peripheral edge of the elastic seal material 1 also inclines in the same direction, and the inner peripheral edge on the front side of the elastic outer peripheral edge of the shield excavator A. Is brought into contact with. Therefore, even if the elastic seal material 1 tries to bend in the direction in which it is folded back forward due to the frictional force with the shield excavator A as the shield excavator A advances, the elastic seal material 1 is blocked by the curl prevention piece 2. Further, by bending the inner end portion 2a of the curl prevention piece 2 rearward, the inner peripheral edge of the elastic seal material 1 does not slide on the shield excavator A and the inner peripheral surface of the elastic seal material 1 does not slide. The sliding force is reduced to reduce the acting force of refraction, and an excessive bending force is not applied to the curl prevention piece 2.

When the sheath pipe D is further moved into the reaching shaft C and the shield excavator A is propelled, the elastic seal material 1 is separated from the outer peripheral surface of the sheath pipe D and the shield excavator A is removed.
The elastic seal material 1 is pressed against the outer peripheral surface of the
Is inclined in the direction opposite to the approach direction of
Prevent the inflow of groundwater into the interior. When the shield excavator A is propelled from this state, the inner peripheral edge of the elastic seal material 1 tries to buckle in the traveling direction of the shield excavator A due to the frictional force with the shield excavator A. Since the curl prevention piece 2 is fixed to the edge portion, the action direction of the inner peripheral edge of the elastic seal material 1 due to the frictional force becomes incapable of buckling, and the direction in which the outer peripheral surface of the shield excavator A bites. Acts and presses firmly.

In the above embodiment, when the outer end of the curl prevention piece 2 has such a length as to reach the vicinity of the inner peripheral surface of the wellhead B, the elastic sealing material 1 is not affected by the pressure of groundwater or the like. Is not likely to largely bulge and deform toward the reaching shaft C, but when the length is short and the elastic seal material portion between the outer edge and the inner peripheral surface of the wellhead B is wide, the portion Is curved and swelled to the front side (the side of the reaching shaft C) by the pressure of groundwater, and the elastic seal material 1 provided with the curl prevention piece 2 escapes forward in accordance with the propulsion of the shield excavator A and reaches the inclination shaft. In this case, since there is a possibility that it will be turned to the C side,
As shown in FIGS. 5 and 6, strip-shaped pressing pieces 6 are arranged on the front side of the elastic sealing material 1 at appropriate intervals in the circumferential direction.

This pressing piece 6 swings its outer end part back and forth by a shaft 8 to the inner end edge of a fixing piece 6a fixed to the front surface of the elastic seal material 1 by a bolt or the like via a spacer member 7 having an appropriate thickness. It is freely pivoted and has a length shorter than the width between the inner and outer peripheral edges of the elastic seal material 1, and the inner end (tip) from the inner peripheral end of the wellhead B to the outer end of the curl prevention piece 2. It hangs in the direction of the inner diameter to the position where it covers. It is desirable that each pressing piece 6 is always urged by a spring (not shown) wound around the shaft 8 in a direction in which the tip of the pressing piece 6 contacts the front surface of the elastic seal material 1.

With this construction, as shown in FIG. 7, when the shield excavator A is propelled into the reaching shaft C and the inner peripheral edge of the elastic seal material 1 is pressed against its outer peripheral surface. In this state, the pressing piece 6 is also slidably contacted with the shield excavator A in the same inclination direction, and in this state, even if the elastic sealing material 1 expands forward and bends due to the pressure of groundwater or the like, the pressing piece 6 is pressed down. The front surface of the piece 6 is received by the piece 6 to prevent further bending.

[0024]

As described above, according to the seal structure of the reaching shaft of the present invention, the ring-shaped elastic sealing material having a circular hole having a diameter smaller than the outer diameter of the shield excavator at the reaching hole is concentric with the reaching hole. In the seal structure formed by mounting the elastic seal material, strip-shaped curl prevention pieces are fixed or embedded at appropriate intervals in the circumferential direction at the tip of the shield excavator arrival side rear surface of the elastic seal material. It is possible to reliably prevent the inner peripheral edge of the ring-shaped elastic seal material from bending in the advancing direction of the shield excavator by the curl prevention piece, and the elastic seal material is inclined rearward on the outer peripheral surface of the shield excavator. It is possible to prevent the inflow of groundwater, excavated earth and sand, etc., to the reaching shaft by press-contacting in the state where it was made.

Further, by bending the tip end of the curl prevention piece and the inner peripheral end of the elastic seal material toward the rear, the front side of the inner peripheral end of the elastic seal material is surely secured in the shield excavator. It is possible to press-contact the outer peripheral surface, and it is possible to more firmly prevent the elastic seal material from being inverted and bent forward by the frictional force with the shield excavator.

Further, strip-shaped pressing pieces whose length is shorter than the width between the inner and outer peripheral edges of the elastic sealing material are arranged on the front surface of the elastic sealing material at appropriate intervals in the circumferential direction, and the base of each pressing piece is elastic. If it is pivotally attached to the seal material so as to be rotatable back and forth, the pressing piece receives the front surface of the elastic seal material and prevents the elastic seal material from expanding forward due to the intrusion pressure of groundwater or the like. It is possible to prevent it, and the elastic sealing material is always brought into pressure contact with the outer peripheral surface of the shield excavator to achieve a predetermined sealing effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an elastic sealing material,

FIG. 2 is a rear view thereof,

FIG. 3 is a simplified vertical sectional side view showing a use state,

FIG. 4 is an enlarged vertical cross-sectional side view of a main part for explaining the operation thereof.

FIG. 5 is a vertical sectional side view showing another embodiment of the present invention,

FIG. 6 is a front view thereof,

FIG. 7 is a vertical cross-sectional side view for explaining the operation,

FIG. 8 is a simplified vertical sectional side view showing a conventional example,

FIG. 9 is a simplified vertical sectional side view for explaining the operation.

FIG. 10 is a simplified vertical sectional side view showing a state where the sealing material is bent.

[Explanation of symbols]

 1 Elastic seal material 2 Roll-up prevention piece 6 Holding piece A Shield excavator B Wellhead C Arrival shaft

Claims (3)

[Claims] 1. A seal structure in which a ring-shaped elastic seal material having a circular hole having a diameter smaller than the outer diameter of a shield excavator is attached to the reaching wellhead concentrically with the reaching wellhead. A seal structure for a reaching wellhead of a shield excavator, characterized in that strip-shaped curl prevention pieces are fixed or embedded at appropriate intervals in a circumferential direction on a rear surface of a machine arrival side. 2. A strip-shaped pressing piece having a length shorter than the width between the inner and outer peripheral edges of the elastic sealing material is arranged on the front surface of the elastic sealing material provided with the curl prevention piece at appropriate intervals in the circumferential direction. 2. The seal structure for the reaching wellhead of a shield excavator according to claim 1, wherein the base of each pressing piece is pivotally attached to the elastic seal material so as to be rotatable back and forth. 3. The shield excavator according to claim 1 or 2, wherein the tip end portion of the curl prevention piece and the inner peripheral end portion of the elastic sealing material are bent rearward. Wellhead seal structure.